<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" @click="handleBackClick" v-show="showAbs"><span
      class="iconfont header-abs-back">&#xe624;</span>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link to="/">
        <div class="header-fixed-text">景点详情</div>
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
    </div>
  </div>
</template>

<script>
  export default {
    name: 'DetailHeader',
    methods: {
      handleBackClick: function () {
        this.$emit('back')
      },
      handleScoll: function () {
        const top = document.documentElement.scrollTop
        if (top > 60) {
          let opacity = top / 140
          opacity = opacity > 1 ? 1 : opacity
          this.opacityStyle = {
            opacity: opacity
          }
          this.showAbs = false
        } else {
          this.showAbs = true
        }
      }
    },
    data () {
      return {
        showAbs: true,
        opacityStyle: {
          opacity: 0
        }
      }
    },
    activated: function () {
      window.addEventListener('scroll', this.handleScoll)
    },
    deactivated: function () {
      window.removeEventListener('scroll', this.handleScoll)
    }
  }
</script>

<style lang="stylus" scoped>
  @import "~styles/varibles.styl";

  .header-abs {
    position: absolute;
    left: .2rem;
    top: .2rem;
    width: .8rem;
    height: .8rem;
    border-radius: .4rem;
    background: black;
    text-align: center;
    line-height: .8rem;
  }

  .header-abs-back {
    color: white;
    font-size: .4rem;
  }

  .header-fixed {
    z-index 2
    position: fixed;
    top 0
    left 0
    right 0
    height: $headerHeight;
    line-height $headerHeight;
    background $bgColor
    font-size .32rem
    color white
    text-align center
  }

  .header-fixed-text {
    color white
    font-size .32rem
  }

  .header-fixed-back {
    position absolute
    width .64rem;
    text-align center;
    font-size .4rem;
    top 0
    left 0
    color white
  }
</style>
